Qt 5.1 has been released. It brings several enhancements, Qt Quick Controls, Qt Sensors, a much better C++11, Wayland and OpenGL support, and the development of Android and iOS applications is very usable for a large number of use cases. In related news, the LXDE desktop prepares the change to Qt.

Honestly, that'd surprise me. No matter how you feel about it, GTK is probably the most popular GUI library for major and commercial software packages on Linux largely thanks to Red Hat's immense popularity in the commercial world. Sure, I suspect GTK3 is considerably less popular than it's predecessor but I'd be extremely shocked to see Mozilla start shipping Firefox with the XUL-QT backend or the MySQL admin tools to suddenly be ported to something else.

Is QT a dream to work with? Does it work extremely well on most common platforms? Yes to both. Do I think it'll suddenly become more popular than GTK in the Linux world? I doubt it.